mmg_233_2013_genetics_genomicswikiaorg-20200214-history
Golden Rice
Stanley Cohen and Herbert Boyer were the first scientists to recombine genes and create the first multiple drug resistant Escherichia coli ''(1). The discovery of chimeric DNA molecules that could produce functional protein products led to an explosion in recombinant gene products that are now involved in a astronomical number of industrial, medical, agricultural, and scientific processes. For example, the production of insulin through recombinant DNA, which was originally obtained from animal sources, increased availability drastically and also reduced cost (2). Another product of the recombinant DNA breakthrough was a genetically engineered strain of ''Oryza sativa simply known as Golden Rice. The enhanced genome of the rice now enabled the plant to bio-synthesize beta-carotene (B-carotene), the pro form of vitamin A (2). This elegant creation was successful at reducing the deaths of some 500,000+ children that were dying per year from vitamin A deficiencies at that time (2). The History Golden rice the brainchild of Ingo Potrykus (Swiss Federal Institute of Technology) and Peter Beyer's (University of Freiburg). The main goal was to design a vitamin A enriched food that could be easily cultivated in regions where vitamin A deficiency was rampant like Asia and Africa. The pair worked on the project for over 8 years before publishing the results in Science in 2000. Rice naturally produces B-carotene, but only in the leaves which are not edible (2). The major obstacle that Potrykus and Beyer overcame was getting the plant to express B-carotene in the edible part of the plant, the endosperm (2). The Recombination In order to synthesize B-carotene, immature rice endosperm need 3 additional non-endogenous enzymes; phytoene desaturase, c-carotene desaturase, and lycopene B-cyclase (3). Agrobacterium-mediated transfer was utilized, with three vectors, in one transformation to insert a majority of the B-carotene pathway (Figure 1). Traditional white rices can produce gernaylgernayl diphosphate (phytoene synthase), but without phytoene desaturase are unable to convert phytoene to c-carotene. C-carotene desaturase and lycopene B-cyclase further convert c-carotene to lycopene and then onto B-carotene (3). B-carotene can then be converted to vitamin A by beta-carotene 15,15'-monooxygenase (2). The Next Best Thing Golden rice remains on the frontline of the GMO battle between activist groups like Greenpeace and both corporations and health organizations. Originally criticized for its low B-carotene content, Golden rice has been updated and now contains a twenty fold increase in B-carotene (4). Although its nutritional upgrades were confirmed, Golden Rice remains a controversial topic as it lies in an ethical grey zone between humanitarian effort and GMOs for profit. The patent for Golden Rice was levied against the technologies needed to create it and produce it on a global scale. In order to accomplish this goal the universities of the developers had to pair with the commercial agriculture company Syngenta (5). Syngenta provided the necessary resources to both complete the Golden Rice project and then bring it to a testable scale. However, Syngenta is still a large agri-business conglomerate with ties to companies like Monsanto. References 1. http://www.dnalc.org/view/15915-The-first-recombinant-DNA.html 2. http://en.wikipedia.org/wiki/Recombinant_DNA 3. Engineering the Provitamin A (β-Carotene) Bio-synthetic Pathway into (Carotenoid-Free) Rice Endosperm. Xudong Ye, Salim Al-Babili, Andreas Klöti, Jing Zhang, Paola Lucca, Peter Beyer, and Ingo Potrykus. Science 14 January 2000: 287 (5451), 303-305. [DOI:10.1126/science.287.5451.303] 4. Grusak MA. 2005. Golden Rice gets a boost from maize. Nat Biotech 23: 429-30 5. http://www.goldenrice.org/Content1-Who/who4_IP.php